Overwintering
As winter approaches, darkening shades of brown, skeletal trees, leaf litter and empty flowerbeds, often under leaden skies, fill the view through the window. November wraps the landscape in damp and desolation and the vivid colours of summer are a memory. But though hidden and secret, wildlife is there, and needs your protection. The butterflies and bees of next year are there. Your garden, importantly, continues to be the habitat and refuge it was through spring and summer, only now, in low temperatures, shorter daylight hours, and an absence of food, grim survival is necessary. Wildlife achieves this, and then subsequent rebirth in different ways.
Some shelter is gained "where dead leaves upward and downward scatter" (Edward Thomas, poet 1878 - 1917),
or in places kept evergreen by lichens, moss or bramble, skeleton weeds, rough long grasses, and crevices and hollows in trees. These micro-habitats are sought by insects. Some native butterflies will create little hammocks on plant stems, the Browntail will construct a white silk tent which can be seen on twigs and branches. Although all males die before winter, some butterflies overwinter as caterpillars, others as eggs or a chrysalis. Bees nest beneath the soil, often in bare patches on a lawn. Some insects build cavities in hollow stems of plants. Ants move deep into the anthill and plug the entrance with plant remains. During their long winter sojourn, known as a diapause, all bodily activity slows, then ceases, growth is suspended and fat reserves keep the insects in a torpor just above actual death. It was discovered in the 1950s that in winter, many insects lose part of their water content and replace with glycerol, a natural anti-freeze, that prevents the formation of crystals at low temperatures.
Many adult insects will die, but they have ensured survival of their species by leaving behind their descendants, as eggs, larvae or pupae. Among wasps, only the queen will survive, protected by a thick coat, ready to emerge and establish a new colony in spring. Astonishingly, she has kept the sperm from autumn mating in her body throughout the winter. Bee larvae will have been growing through the summer season, will hibernate over winter, and emerge the following spring - a year long process.
Some amphibians will seek ponds - adult male frogs will remain on the pond bed in dormancy. Others go underground, into loose soil or a convenient mammal burrow, beneath sheds or decking, or a handy pond-liner. Reptiles will look for piles of rotting vegetation - as in compost heaps, heat will be generated during decomposition. Fallen trees and branches are desirable winter residences.
Green shield bugs (Palomenaprasina) turn a darker bronze-brown colour to camouflage themselves, and hibernate over winter. Photo : Stu's Images Wikki commons
And so one must conclude from this that the consideration to wildlife shown by gardeners, cannot be for three seasons out of four. We can still lend a hand and help ensure that insects and other creatures will reach next summer successfully. Allow yourself to be a little untidy. The leaves around the bases of shrubs and trees and on flower beds could be left. Leave valuable green food sources until spring. If you cut reasonably stout flower stalks, leave some at different heights. Those you remove could be tied into bundles and left around the garden. Dead hedges of course are brilliant for overwintering insects and creatures. Beetle banks are used by farmers to encourage beneficial insects, but they could be introduced in a garden as an additional rich habitat to help the thousands of fascinating beetles in this country. A raised strip of grass, perhaps beneath a hedge, would offer sanctuary and shelter. Apparently beetle banks find their own equilibrium and do not need mowing, but could be sown with some wild flowers. If you already have a compost heap and a pond, your garden will be very appealing to wildlife. However a corner (out of obvious sight) for a heap of leaves and vegetation which you would be willing to leave would also be a life-saver to many. A terra cotta pot on its side, stuffed with vegetation and twigs will be helpful and you can make, or buy insect homes. Finally, it is worth remembering that artificial light is extraordinarily damaging to wildlife. If you have lighting, it is possible to ensure that it is responsive to movement only and points downward.
December 2024
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